1. Field of the Invention
The present invention relates to a video signal recording apparatus which is called an authoring apparatus to form, for example, one video signal from the video signal recorded on a plurality of recording media and record this video signal to a recording medium and a video signal recording method which is preferably applied to this authoring apparatus which is used by a manufacturer, etc. for manufacturing a recording medium in which a video signal is recorded.
2. Description of the Related Art
Nowadays, a variety of the reproducing apparatus of digital VTR and DVD (Digital Video DiSC) and software which may be reproduced utilizing these apparatuses have been offered. Accordingly, it is now possible at home to easily reproduce the digital video signal and voice signal to enjoy high quality and high fidelity image and sound.
Moreover, a large amount of digital video and voice signals or programs have also been offered by way of a recording medium such as CD-ROM (Compact Disc ROM) and thereby it is now also possible to widely use digital software provided via the CD-ROM by utilizing a personal computer.
However, here rises a problem, on the other hand, that softwares such as digital video signals which are offered with a large amount of information may be duplicated without any limitation. Therefore, when the digital information, for example, the digital video signal is processed, a direct duplication preventing control such as inhibition of duplication is effectuated by adding a duplication control information consisting of a duplication preventing code or a duplication generation limiting code to a digital video signal and then recording the information and video signal to a recording medium.
For example, in the side of the manufacturer of a recording medium in which an information signal such as a digital video signal, for example, is recorded, an original recording medium in which the information signal such as the digital video signal used for the mastering is produced utilizing an information signal recording apparatus which is called an authoring apparatus.
This authoring apparatus receives a supply of a plurality of information sources, for example, a digital video signal recorded in a plurality of recording media, forms a digital video signal to be recorded by editing these digital video signals and then records such digital video signal to a recording medium.
In this case, a duplication control information indicating the contents of the duplication control such as acknowledgment of duplication, inhibition of duplication and limitation on generation of duplication is added in direct, for the main information signal such as the header of data in block units, to the digital video signal as the main information signal recorded on the recording medium. Thereby, the digital video signal as the main information signal and the duplication control information as the additional information are recorded on the recording medium.
In the case where a recording medium in which an information signal is recorded through the mastering is manufactured depending on the recording medium produced as explained above, the digital video signal and the duplication control information for the relevant digital video signal are recorded on the recording medium manufactured as explained above.
Moreover, when it is attempted to duplicate the digital video signal recorded on the manufactured recording medium to the other recording medium, the information recorded on the relevant recording medium is reproduced utilizing a digital reproducing apparatus to obtain the duplication control information together with the digital video signal and these signals obtained are then sent to a digital recording apparatus via the digital transmission line.
In the digital recording apparatus, the duplication control information is detected from the information received through the digital transmission line to discriminate contents of the duplication control. Thereby, recording control of the input digital video signal is conducted depending on such discrimination result.
For example, when contents of the duplication control indicated by the duplication control information acknowledge duplication of the digital video signal, the input digital video signal is converted to the digital information which is suitable for recording and recording (duplication) is executed by writing such digital information to a recording medium for recording. Meanwhile, contents of the duplication control indicated by the detected duplication control signal inhibit duplication, recording (duplication) of the input digital video signal is not executed.
Moreover, when contents of the duplication control indicated by the duplication control information acknowledge only the duplication of the first generation, the input digital video signal is converted to the digital information which is suitable for recording, it is then written to the recording medium for recording to execute the recording. Simultaneously, the duplication control information as the additional information is changed to the information instructing inhibition of duplication (inhibition of duplication of the next generation) and it is then recorded in the recording medium for recording. Therefore, it is impossible to further duplicate the duplicated digital video signal utilizing the duplicated recording medium for recording.
As explained above, in the case of the so-called digital connection where a main information signal and a duplication control information as the additional information are supplied to a recording apparatus as the digital signals, since the duplication control information is included in the digital data to be transmitted, the duplication control such as inhibition of duplication can surely be realized in the recording apparatus utilizing this duplication control information.
Even in the case of obtaining the digital video signal and the duplication control information by reproducing, with a digital reproducing apparatus, the information recorded in the recording medium where the digital video signal as the main information signal and the duplication control information as the additional information are recorded as explained above, only the digital video signal which is the main information signal is converted to an analog signal through a D/A converting circuit and is then led, for example, to monitor the display image, to an analog output terminal which is usually connected with a monitor receiver.
As explained above, even in the case of the reproducing apparatus for the digital information, the analog signal led to the analog output terminal does not include the duplication control signal. Therefore, in the case of the analog connection in which an analog VTR is connected to the analog output terminal, duplication of the main information signal is possible.
Moreover, even in the digital connection, since the duplication control information is often added separated from the digital video signal as the main information signal of the header section, it is probable that duplication of the main information signal is possible by erasing the information of the part where the duplication control information is added or by alteration of information such as replacement with the other information.
Moreover, even when the video signal and voice signal as the main information signals are analog signals or digital signals, if the duplication control information is superimposed or added to the frequency band which is different from the frequency band of the video signal and voice signal, the duplication control information is eliminated by a frequency filter of the simplified structure and duplication of the main information signal becomes possible.
Considering the background explained above, it is therefore an object of the present invention to add an additional information to an information signal in such a manner that reproducing quality of the information signal is never deteriorated and alteration and erasure of the additional information are impossible.
The video signal recording apparatus of the present invention is characterized in comprising a timing signal generating means for generating a timing signal based on the synchronous signal of the video signal, a spectrum spread code generating means for generating a spectrum spread code signal synchronously with the timing signal, an additional information signal producing means for producing an additional information signal to be added the video signal, a spectrum spreading means for spreading the spectrum of the additional information signal with the spectrum spreading signal, a signal adding means for adding the spectrum spread additional information signal to the video signal to output the video signal for the recording operation and a signal writing means for recording the video signal for recording sent from the signal adding means to a recording medium.
According to the video signal recording apparatus of the present invention, the additional information is spectrum spread and superimposed to the information signal in the same time and within the same frequency band. The information signal to which the spectrum spread additional information is superimposed is then recorded in a recording medium.
The additional information is spectrum spread and is superimposed as a wide band and low level signal to the digital information signal itself. Therefore, the additional information will never deteriorate the information signal. Moreover, since the additional information is superimposed to the information signal itself, it becomes impossible to alter and erase the additional information through replacement of the frequency filter and only of the information signal in such a case that the relevant information signal is reproduced and transmitted. Moreover, even when the information signal is a digital signal and it is converted to an analog signal, the additional information is never eliminated because the additional information is superimposed on the information signal in the same time and within the same frequency band as explained above.
Thereby, it becomes possible to surely provide the information signal and the additional information added thereto, for example, in the recording apparatus side. Accordingly, when the additional information indicates, for example, the contents of the duplication control, the recording control can be surely executed in the recording apparatus side depending on the relevant additional information. When the additional information is used for the purpose of copyright protection as explained above, the copyright can be protected extensively.
Moreover, the information signal recording apparatus of the present invention is provided with an adding means for adding the additional information sent from the additional information generating means to the video signal.
Thereby, an additional information is added to the information signal and the spectrum spread additional information is superimposed to the information signal. For example, the additional information is added by the adding method to the information signal, for example, in such a manner that the additional information is stored to a header of the recording medium in which the digital information signal is recorded or added through insertion to the digital information signal and the spectrum spread additional information is also superimposed on the digital information signal.
Therefore, reliability and strength of the additional information added to the information signal can be enhanced so that the other additional information added by the method different from one method can remain even if one additional information is altered or erased, by adding and superimposing, for example, the additional information of the same contents with a different method. Moreover, it is also possible here to add the additional information of different contents to the information signal by the different method. In this case the, total amount of the additional information for the information signal can be increased.